Incarcerated adolescents represent a group at high risk for health consequences associated with risky sexual behaviors. They report greater participation in a number of sexual risk behaviors (including sexual risk in conjunction with drug use), higher rates of sexually transmitted diseases (STDs) and pregnancy than their non-detained adolescent peers. Adolescents, including incarcerated teens, report sexual behavior both with partners with whom there is a relationship (main partners) and partners with whom there may be a friendship or only an acquaintance (non-main partners). Condom use is more common with non-main than main sex partners and substance use in conjunction with sexual risk also appears to vary by partner type. The long-term objective of this research program is to reduce HIV risk behavior among adolescents involved in the criminal justice system who abuse non-injection drugs by developing and establishing the efficacy of an intervention that includes a specific focus on partner-specific decision-making and behavior through presenting relevant information, enhancement of prevention motivation, opportunities to learn and -practice safer sex behavioral skills, and sexual decision-making in conjunction with substance use. Furthermore, we seek to advance knowledge of the mechanisms of action by which interventions reduce HIV risk behavior. In the present application, we propose to develop and pilot test a partner-specific HIV risk reduction intervention for incarcerated adolescents who report substance abuse. In the first phase of the study we will pilot the intervention with 20 incarcerated adolescents and elicit their feedback regarding their experiences and perceptions of the intervention. Following refinement of the intervention, we will conduct a small randomized trial (n=60) to examine the efficacy of the intervention relative to a healthy lifestyles psychoeducation intervention (HLS). We expect that, relative to CBT-SA), participants randomized to the intervention condition will have lower levels of sex-related HIV risk behavior and of substance use in conjunction with sexual risk. We will also examine the potential mechanisms by which the intervention produces a reduction in health risk behaviors. If found to be efficacious, this intervention will help to reduce the acquisition of HIV among substance using incarcerated adolescents.